The present invention generally relates to a nano-supported sponge catalyst on a substrate, and more particularly to a nano-supported sponge catalyst on a substrate for nanotube growth.
A nanotube, and more specifically a carbon nanotube, is known to be useful for providing electron emission in a vacuum device, such as a field emission display. The use of a carbon nanotube as an electron emitter has reduced the cost of vacuum devices, including the cost of a field emission display. The reduction in cost of the field emission display has been obtained with the carbon nanotube replacing other electron emitters (e.g., a Spindt tip), which generally have higher fabrication costs as compared to a carbon nanotube based electron emitter.
The manufacturing costs for vacuum devices (e.g., a field emission display) that use a carbon nanotube can be further reduced if the carbon nanotube is grown on the field emission substrate from a catalytic surface using chemical vapor deposition or other film deposition techniques. Nanotube growth can be conducted as a last deposition process preventing the degradation of the electron emitter properties by other device processing techniques or steps (e.g., wet processes). To further reduce costs for vacuum devices, it is also desirable to construct the field emission substrate from materials such as borosilicate glass or sodalime glass. However, borosilicate glass and sodalime glass cannot generally tolerate temperatures above about sixty hundred and fifty degrees Celsius (650xc2x0 C.). In addition, the tolerance of borosilicate glass and sodalime glass is further reduced if the borosilicate glass or sodalime glass is subjected to temperatures above about sixty hundred and fifty degrees Celsius (650xc2x0 C.) for an extended period or forces are applied to the borosilicate glass or sodalime glass at such temperatures.
In view of the foregoing, it is desirable to provide a nano-supported sponge catalyst on a field emission substrate for carbon nanotube growth that allows such a carbon nanotube to be grown on the field emission substrate that has a deformation temperature below about six hundred and fifty degrees Celsius (650xc2x0 C.). Furthermore, additional desirable features will become apparent to one skilled in the art from the drawings, foregoing background of the invention and following detailed description of a preferred exemplary embodiment, and appended claims.